Tag: biology

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    “Plants That Explode”

    We often think of plants as passive and stationary, but the truth is that some plants move faster than we can even see. In this “True Facts” video, Ze Frank takes a look at a whole host of fast-moving plants, including horsetail plant spores that walk and jump, trebuchet-like bunchberry dogwood, vortex-ring-shooting moss, and moisture-driven self-digging seeds. These plants all use clever mechanisms that leverage water to spread the plant’s reproductive material at little to no energy cost to the plant itself. (Video and image credit: Z. Frank)

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    “The Art of Flying”

    Like schools of fish, starlings gather in massive undulating crowds. Known as murmurations, these gatherings are a type of collective motion. Scientists often try to mimic these groups through simulations and lab experiments where individuals in a swarm obey simple rules that depend only on observing their neighbors. It requires very little, it turns out, to form swarms that move in this beautiful manner! (Video and image credit: J. van IJken; via Colossal)

  • Saving Energy By Following a Leader

    Saving Energy By Following a Leader

    Scientists have long suspected that birds save energy by following a leader — think of the V-shaped flight formation used by geese — but a new study captures that savings directly. The team studied starlings, flying singly or in groups of two or three, in a special wind tunnel. Each bird wore a tiny backpack with sensors and lights that captured its motion and helped researchers identify it individually in videos. And, using before and after metabolic measurements, the researchers could pin down exactly how much energy each bird used when flying.

    They found that birds who spent most of the flight in a “follower” position used up to 25% less energy than they did when flying solo. That’s a major incentive to follow someone else. Interestingly, they also found that the most efficient solo fliers were the birds most likely to take on the “leader” position. The team notes that these “leaders” tend to use a lower wing-flapping frequency, but a full explanation of how they save energy will require a follow-up study. (Image credit: R. Gissler and S. Hao; research credit: S. Friman et al.; via Physics World)

  • How to Run on Water

    How to Run on Water

    Ahead of the Olympics, I’ve written a feature article for Physics World that explores how basilisk lizards and grebes run on water and what it would take for a human runner to do the same. Check it out! (Image credit: B. Mate; see Physics World)

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    Wasps in Flight

    Personally, I’ve had some bad encounters with wasps, but Dr. Adrian Smith of Ant Lab feels the insects receive short shrift. In this video, he shows many species in the order — most of which are venomless and stingless. In high-speed video, their flight is mesmerizing. Wasps have separate fore- and hindwings, but during flight, they move them like a single wing. Velcro-like hooks on the edges of the wings hold the two together.

    From a mechanics perspective, I find this fascinating. Aerodynamically, I’d expect much greater benefits from one large wing over two small ones, but outside of flight, separate wings are more easily tucked away. It’s so neat that wasps have a way to enjoy the benefits of both, enabled by a simple but secure line of hooks. (Video and image credit: Ant Lab/A. Smith)

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    Fish Ladders Keep Species Swimming

    Dams often use fish ladders to help migratory species make their way upstream without interruption. In this video, Grady from Practical Engineering discusses some of the considerations that go into this special infrastructure and what kinds of designs work for different species. The first challenge for any dam is attracting fish to the ladder, which is often done by regulating the water flow at the entrance to create the velocity and turbulence that fish look for when going upstream.

    Once fish are in the ladder, they travel up a series of jumps that break the dam’s elevation into manageable steps. Different dams use various baffle designs to create jumps suited to their local species and the way they like to swim. Calmer spots in each section give fish a spot to rest before they carry on. In well-designed systems, the vast majority (97%!) of fish that enter a ladder make it through to the other side. (Video and image credit: Practical Engineering)

    Fediverse Reactions
  • Sensing Sound Like Spiderwebs

    Sensing Sound Like Spiderwebs

    Most microphones — like our ears — work by sensing the tiny pressure changes caused by a sound wave‘s passing. But for microphones built this way, the smaller they get, the more sensitive they are to thermal noise. That’s one reason that the tiny microphones in a laptop or webcam just don’t sound as good as larger mics.

    Researchers turned to nature to look for alternative ways to measure sound and zeroed in on the mechanism spiders use. Spiders “listen” to their web’s vibrations; the tiny strands of silk quiver as air flow from a sound moves past. Instead of being pressure-based, this mechanism uses viscous drag to register a sound.

    The team fabricated an array of microbeams to test the concept of a viscosity-based microphone and found that tiny beams sensed sounds just as well as larger ones. That means these microphones can get smaller without sacrificing performance. For now, they’re not as sensitive as conventional microphones, but that’s not surprising, given that engineers have been improving pressure-based microphones for 150 years. It’s a promising start for a new technology, though. (Image credit: N. Fewings; research credit: J. Lai et al.; via APS Physics)

  • “Through the Bubbles”

    “Through the Bubbles”

    Many seabirds catch their prey through plunge diving, where they fly to a particular height, then fold their wings, and dive into the ocean. In busy waters, bubbles from all this diving can help obscure the birds from hapless fish. Some birds even use bubbles to escape from their own predators; some penguin species, for example, release trapped air from beneath their feathers as they surface, creating a flurry of bubbles that reduce the drag they have to overcome as they make their exit from the water. The fast exit and bubbly wake help them escape prowling seals. (Image credit: H. Spiers; via BWPA)

  • Universal Wingbeats

    Universal Wingbeats

    Eagles, butterflies, and whales don’t appear to have much in common, but a new study shows that they — along with over 400 other flying and swimming animals of all sizes — flap with a frequency determined by a simple equation. Their beat frequency is proportional to the square root of their mass divided by their wing area. As you can see in the graph below, this scaling collapses pretty much all of the data onto a single line:

    Illustration of the predicted relationship between size and wing freequency (black line) shown alongside various insects, birds, bats, penguins, and whales. The swimming animals also fall on the line, once adjustments are made for the difference in density between air and water.
    Illustration of the predicted relationship between size and wing frequency (black line) shown alongside various insects, birds, bats, penguins, and whales. The swimming animals also fall on the line, once adjustments are made for the difference in density between air and water.

    It’s surprising to find such a consistent relationship among animals of such vastly different sizes and types. The next big question for researchers will be unpicking exactly why and how animals evolved to use such a consistent pattern between their size and their wing(/fin) frequency. (Image credit: top – E. Ward, graph – J. Jensen et al.; research credit: J. Jensen et al.; via Physics World)

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    Building In a Stingless Hive

    Honeybees, with their stingers, get lots of attention, but the Americas have plenty of stinger-less honeymakers, too. These stingless bees are native to Mexico, where beekeepers cultivate them for pollination. Without stingers and venom, the bees use their building prowess to keep out unwanted visitors. Much of the hive — from the entrance’s nightly gate to the pods where young are stored — is built from cerumen, a substance the bees create by mixing wax with resins they collect from nearby trees. Just as they do with pollen, worker bees collect drops of resin and store them on their hind legs before flying back to the hive. The viscous fluid sticks well, until a swipe of a leg shears it enough to lower its viscosity and slide it off. (Video and image credit: Deep Look)